Quality control is an important stage in the mass production of semiconductor devices. By semiconductor devices, the present invention refers to not only semiconductor chips but also printed circuit boards. However, known methods of meeting quality control of the outputs from semiconductor device production lines require electrical signals to be send to leads of semiconductor devices and response measured therefrom before further packaging of such devices occurs. Such testing not only poses a bottleneck in the overall speed of production of semiconductor devices but also is a source for damaging such devices if the transfer of semiconductor devices to and forth the testing position is not handled properly.
Test handlers have been used in the electronics industry to transfer semiconductor devices into testing positions for testing the integrity of such devices. The testing positions usually have testing enclosures or chambers for receiving the semiconductor devices on known conveying systems. Test handlers within the testing enclosure pick up semiconductor devices, move them vertically upwards, turn them through an angle of 90 degrees in the same plane, move them forward to the test rig, and then reverse the movement to return the tested devices to the conveying system. Thereafter, the tested semiconductor devices are offloaded.
The speed and accuracy of test handler in picking up devices from the conveying system; placing them in testing positions within the testing enclosures; and returning them to the conveying systems are key factors in assessing the overall performance of a test handler. Lately, a third factor is receiving attention: the ability of a test handler to accept large variety of package sizes of semiconductor devices for testing with minimum down time in tool change.